It is known to provide mats and trays to protect the floor surfaces of vehicle foot wells. Where such a mat or tray (hereinafter generically referred to as a “mat”) consists of or comprises a fluid-impermeable layer such as one made out of rubber or a thermoplastic polymer, the mat provides effective protection of the underlying surface from water and waterborne materials, such as snow, slush, grit, mud and various spilled foods and beverages. This is particularly desirable when, as is now common, the underlying vehicle foot well surface is carpeted.
Because the mat is not permanently affixed to the vehicle, it may have a tendency to slip about in the foot well. It is now common for vehicle manufacturers (“OEMs”) to install mat retention devices at least in the driver's side foot well to prevent the displacement of the mat from where it is supposed to be. Even where the OEM does not furnish such mat retention devices, an aftermarket supplier of mats sometimes does. One such mat retention device can be seen in U.S. Pat. No. 9,199,567, assigned to the Applicant and incorporated by reference herein. A mat retention device usually will have a retention post that stands up from the foot well surface. It is common to receive these retention posts in holes made for them in the floor mats. But the creation of retention post holes in a floor mat breaches the fluid barrier and may permit fluid to leak onto the carpet through the hole. This problem becomes worse where the vehicle is subjected to winter or muddy conditions.